Truing and positioning device for grinding wheels



June 16, 1931.

c. H. scHuRR TRUING AND P .OSITIONING DEVICE FOR GRINDING WHEELS Original Filed May 15, 1922 2 Sheets-S1166?. 1

I N VEN TOR.

r June 16, 1931. H. scHuRR 1,810,408

TRUING AND POSITIONING DEVICE FOR GRINDING WHEELS Original Filed May 151, 1922 ZASheels-Sheecv 2 INVENToR. F19 6 kaf/e5 c/wfr w BY original 'appiiaaqn flied May i5, 1922,

grinding machine in a preselected position Patented Jtme 116,? l1931 c iiN-i'rnnf fsgrif;arri?. Parent-1i. f OFFICE .Gerini-.Es .scr-TURB. QF CLEvELP-ND, 19H10, #Setmana m0, rire teas-sammler COM- vPliner,yor einemstatin, omo, f roaronnT-Ionor omo rnnrnenivn rosirioivinennvion non GRINniNG WHEELS this application v-led January i This invention relates to truing and Ypositioning .devices for `the grinding Wheels of grinding machines Y Oneaof the objects of this 'inve'ntion `ris to provide means for accurately `locating the Workingsurface of the grinding Wheelof a onthemachine whereby it may 'be given a preselected positional relation to the Workito be ground. f

` nother object is to provide means Whereby the Working' 'surface of the grinding Wheel when once so positioned may, in the operation of the machine, be moved away Yfrom said position a known distance corresponding `to ythe amount of material to beA ground from the Work; and then may be returned accurately to said position by feeding-the grinding Wheel intol the Work,thiis accurately grinding away thede'sired amount of material from the Work.

`-to a true surface. j Y

Another object isto provide means Whereby in positioning the grinding Wheel Working surface as abovek stated it-may be also dressed Another object is to provide an improved dressing device in which the dressing element 1 .saidplane.- y

a 'Aiiother object is to-:prov-ide means :by

Serial No. 561,219) and iii GemanylMayz., 1859,35` Divided and 14, 192e. kserial No'. 2465707;

face-of .thewheel may be dressed and positionally adgustedand also with reference to preselected lplanes on the machine-.and to "minii'nize or make negligible the displacevmentor .the wheel acerom said planes by thermal expansion ofthe shaft.A

.Y Another object is to. provide an improved mechanism adapted for use with a grinding machine `for l truing or dressing the planular face of a grinding Wheel, in which the dressing elementinaybe .moved accurately in a plane of preselected position by rotating it about an axis of rotation at right angles rto `which the dressing element .during `.the dressing operation xmay ybe .moved .by .hand with La steady, uniform movement 4.Wherebypthe dressing element lvvill'dress a itrue even surrace on-the wheel.

I f Other objects .Willbe .apparent `to ,those skilled this art from-the followingdeseripti n1oif :the invention, staken in. connection;

`With-the accompanying drawings illustrative maybe accurately retiirnedto or restored to thereof, in which z. "its preselected vdressing position inthe event vthe dressing element.

of misadjustment oriof lWear or renevval'of Ano-therv objeetislto provide means by tion on-thegrinding machine and accurately restored to or maintained in said position, or positions at known distances therefrom.

Another object iste-provide means `Where- -by vthefplanular Working face of thek grind- Y Fig. 3 takenfrom the plane 4l or" Fig. 8;

ing Wheel mayliedressedto coincidence with said preselected plane hy movingthe Wheel into the path of a. moving truing or rdressing element which has been previously accurate- `'ly positioned;

Another object is to provide in connection-.applied thereto flarger scale;

' Fig; l isa-n elevational vieivof apart .of

a gear grinding machine `showing the inven-f f FgQ is avsidesectional view ofthe parts of the gear grinding machine shown in F 1g. land showingthe grinding wheel and .position controlling` mechanism therefor ii'orming 1 theplane' of l, drawntora larger scale, and vkvv'ithsome of the parts broken away;

` Figg iis f a sectional viewy taken vfrom Ythe plane 8-8of Fig. 7

Fig. 9 is a. simplified view, in some respects diagrammatic, of a universal grinding machine showing the invention applied thereto.

The subject matter of this ap lication is divisional from application erial No. 561,219, filed May 15, 1922, which shows in detail a gear grinding machine embodying the instant invention and reference may be had thereto for a more complete description of those elements which are herein merely indicated in ythe drawing and briefly described.

Referring to Fig. 1 at 1 is indicated a vertical column having guides 2-2 upon which is mounted, vertically slidable, a slide 3 carrying a head 4 swivelled thereon about a horizontal axis. By means of an adjusting shaft 5 and gear connections not shown but enclosed within a housing 6a the head may be swivelled. The head 4 comprises a tubular casing 6 closed at one end by a cap 7 and at the opposite end terminating in a grinding wheel hood 8 and is thus adapted to enclose a grinding wheel 9 and a grinding wheel shaft 10. The tubular arm 6 is bored out to receive an axially movable cylindrical quill 11, which carries therein axially immovable thrust ballbearings 12 between a shoulder 13 in the quill and a clamp ring 14 bolted thereto by bolts 15. The shaft 1() is held by the bearings 12 against axial movement in the quill 11 and is guided against lateral or radial movement by sleeve bearings 16 and 17 and `ball-bearings 18 and 19. A driving pulley 20 is mounted on the shaft 10 to drive it and the ball bearing 19, pulley 20, bearings 18 and 17 are all clamped on the shaft by the nut 21 on the lower end of the shaft. Upon a taper 22, on the upper end of the shaft 10 is mounted a wheel clamp plate 23 held thereon by a nut 24 and on the hub 25-thereof is mounted a second clamp. plate 26 held thereon by a nut 27 and between the plates 23 and 26 is clamped the grinding wheel 9. Whereas the shaft 10 rotates within the quill 11, the quill and the shaft are ymovable together yaxially within the tubular arm 6 by the following means, Figs. 1 and3. An adj usting screw 28 terminating on one end in a flanged head 29 is bolted at 30 to the lower end of the quill 11 and is threaded into a nut 31 anchored against axial movement, but free to rotate, between a shoulder 32 on the tubular arm 6 and a clamp ring 33 in the lower end of the tubular arm 6 secured thereto by bolts 34. By turning the nut 31 the screw 28adjustably propels the quill 11 axially and holds it in any adjusted position. To turn the nut 31, worm wheel teeth 35 are provided on the cylindrical periphery of the nut 31 in mesh with the teeth 36 of a worm 37 secured by a nut 38 on a worm shaft 39, the worm and worm yshaft being rotatably supported in a tubular extension v40 on the hollow arm 6.y The rotationV of the worm shaft 39 is adapted to be controlled by means to be described for accurately positioning the quill in the arm 6 and therefore accurately positioning the grinding wheel 9.

The grinding wheel hood 8 on the upper end of the tubular arm 6 is composed of a hood portion 41 bolted as at 42 to the arm 6 and of a hood portion 43 bolted as at 44 to the portion 41.y In the hood portion 41 :to be described.

rl'he grinding wheel 9 in the particular embodiment of the invention under consideration, has a planular face 47 and is adapted to grind the profiles of gear teeth. In Fig. 1 1s shown at 48 a slide mounted for horizontal reciprocation (to the right and left as illustrated) and carrying a gear 49 to be ground. By means not shown but well known in the art, as the slide 48 reciprocates the gear 49 rolls on its pitch circle and the teeth faces thereof engage the grinding wheel planular face 47 with an involute generating movement.

Referring to Figs. 3 to 6 inclusive, means for accurately controlling the above described axial movement of the grinding wheel shaft 10, and therefore of the planular face 47 of the griding wheel 9, is shown. Keyed on the worm shaft 39 by a key 50 is a wheel 51 having notches or tooth spaces 52. Rotatably mounted on the shaft 39 and anchoredagainst axial movement thereon between a collar 53 on the shaft and a face 54 on the wheel 51 is a rhand wheel 55 carrying pivoted thereto at 56 a toothed pawl 57 having a tooth 58 adapted to enter the notches 52 and adapted to be held therein by a tension spring 59 extending fromthe endfof the pawl 57 .to a connection point 60 on the hand wheel 55. Thus the pawl 57 adjustably connects the hand wheel 55 through the wheel 51 to the worm shaft 39 for rotating the latter. In a circular slot 61 on the hand wheel 55, and adjustably secured therein by nuts 64, are two T-bolts 62 andA 262 and a T-bolt 63. projecting ends 62a and 262e of the T-bolts 62 and 262 are longer than the projecting end `63a of T-bolt 63 and the latter is conical as shown for a purpose to be described. On the upper side (Fig. 3) of the extension 40 is a plunger housing 66, in the pocket bore 67 of which is mounted an exteriorly projecting plunger 68, adapted to be retracted into the bore 67 against a compression sprin 69 by a knurled handle head 70 connecte to The eor

` description hereinbefore,V be understood tothe plunger yby'a stem`71: The projecting end of the plunger 68, lies in the rotary path of the T-bolt ends 62a-, 262@ and 63a.

` By means of the construction just described, with the plunger' 68 in the position shown, .the handjwheel may be Arotated in either direction and stop-pedat pre-selected limi-'ts'of angular movement by engagement of thefprojecting ends of the T-bolts 62 and j 262y with the plunger 68 (see Fig. 6)'. Thevv endof T-bolt68 is adapted to-stop the movement ofthe wheel at yan intermediate position but its conical shape permits it to repress and ride overthe plunger 68 and per-y mits the ywheel tobe turnedbeyondthis intermediate position upon the exertiony of sulficienttforce vonthe hand wheel; Movesr` ments of the hand wheel V55 will', from the y *47* ofthe grindingwheel may be moved c from which rises arpost 7 7 (Fig, 7) a Carrying y through a preselected distance between stopped limits of movement when the wheels 55k and 51 are locked together, and the position of this zone of movement thus determined may be preselected by moving the lgrinding wheel when the wheels'55 and 51 are unlocked. I

As shown y'in Fig. 1,.on theoutsidev of the tubular arm 6 isbolted at 7 5-75 lthe base- 76l of a wheel truing or dressing mechanism a barrel 78 within lwhich is rotatably mounted a dresser shaft 79 inthe following manner.

A bushing 80'its the' internal bore of, the

barrel'78`and itself provides a rotative bearingffor an enlarged'portiony 81 of the sha-ft 79'. A flange 82 of the bushing80 provides ancend thrustbearing for an annular face83 on vtheshaft 7 9.V The shaft 79 is adapted to be rotated by means. of'asleeveV 84 surrounding areduced portion y85 of the shaft 79, keyed thereto asl at '86, andhaving, on its cylindrical periphery, worm wheel teeth 87 meshingl with: the teeth 88' of a `wormr 89 rotatably 'mounted' inl an extension 90 onA the upper side (as viewed in the drawings) of the barrel 7 8. The worm is adapted to beturned by a handle'91'secured at 92 to the end ofa worm shaft 93 projecting outwardly through thelbarrel extension 90.' j

The .Sleeve 84vrotates in a bearing bushing 94 which' lits the internal bore of thebarrel 78 and has a iange 95 over-hanging the end y of the barrel 7 Sas shown. The sleeve 84 also has a flange' 96 which over-hangs the flange 95. The reduced portion 85 of the shaft `7 9 terminates in a threaded portion 97 ycarrying a hollow faced nut 98 andbetween lthe nut 98 and the-flange 96 is acompression `spring 99. By means of this construction the spring 99 re-actingv in one direction.

through the flanges 96,95 into one end of the barrel 78 exertsk a force axially in the other direction yon the nut 98 land shaft 79 which holds the shoulder83 rmly without lost mo- Y Ition against thev flange v82Vv and the latter against the opposite end of the barrel 78, thus resiliently taking `up allv lost lmotion of the,y shaft 79. As will alsobe understood from the foregoing description7 the worm 89 may be'osc-illated in either direction by the handle 91 to oscillate theshaft7 9. A laterally extending arm 100 on the shaft 79 terminates.

in a head 101 bored out at 102 andthreaded at 103 to receive the usual or any suitable wheel dresser holder, the particular example illustrated comprising a tubular holder 104 vadjustablythreaded into the head at 103, and

having a hexagon head 105 for adjusting Y it and adapted to be locked in any adjusted position by a well known locking means indicated at 250. In the tubular holder 104 v is threaded aclamp rod 106 which holds, in the end of the holder 104, a diamond or other dressing element 107. The shaft 79 and barr rel 78-are so mounted on the tubular yarm 6 that the rotational axis of the shaft/79 is'parallel to the axis ofy the grinding wheel shaft" 10. It will therefore now beunderstood that when the shaft 79 isoscillated as above described; the diamond or other dressing. ele.- Inent 107 will swing back and forth in a plane which is'at right angles yto the axis ofthe shaft 10 and 4mayb'e'V employed to dress the planular: face planay f c 1 The parts just described are arranged so "that the holder 104 will swing through the doorway 45,y see Figs. -1 and 7. By stopping "theholder yin theyv doorway, the diamon d "or dressing element may be adjusted axially (by turning the'` 'threaded holder 104 inthehead 100y by the liexagon head105) until it justf touches the-wall 46 of the doorway; and then it may be swung inwardly free from the wall 4 46 and then'swung back and forth to dress the face 47 of the'wheel in a plane coincident withor containing the wall or reference station 46. V y

The reference station or wall 46 of the' wheel hood 8, besides being located where it maybe used as aref-erence station to which' to refer theplane 47 of the grinding wheel,

the end thrust bearings 12 of the grinding wheel shaft 10. The plane of the grinding wheel and the'thrust bearings'havingwthis relation to the referencestation, the axial 47 of the'grinding wheel in aV Y is also located in or adjacent to the planefof distance between the bearings andthe plane of the grinding wheel ris so small as to prevent'or minimize to a negligible amount the shifting of the wheel plane out of position by thermal expansion of the shaft upon a rise of temperature thereof.

The/complete operation of the invention will now be described. The dresser is adjusted so that the dressing element 107 thereof will swing in a plane coincident with the wall 46 of thedoorway`45. The pawl 57 on the hand Wheel 55 is raised by hand to disengage the tooth 58 from the toothed Wheel 51 and the wheel 51 is rotated by hand rotating the worm 37 and worm wheel or nut 31 and propelling the screw 28, quill 11, shaft 10 and finally grinding wheel 9, until the planular face 47 of the wheel is brought approximately into the path of the diamond or dressing element 107. The pawl 57 is then released and the tooth 58 locks the hand wheel 55 and kwheel 51together and then by turning the wheel the face 47 is broughtv accurately into the path of the diamond 107. The wheel dresser is then operated by turning the handle 91 a numberof revolutions in alternate directions swinging the diamond 107 back and kforth over the-path .108, Fig. 7, dressing the dressing element or in other words lthereafter stop it accurately in the preselected plane of the Wall or reference station 46 j above described. The hand wheel 55 is now lturned in the yopposite direction to move the face 47 of the wheel away from the preselected plane by an amount equal to the total amount it is desired to grind off of the vtooth faces of the workgear 49. VlVth the yWith the'gear thus positioned, and with the machine 1n operation the hand wheel 55 is rotated until the intermediate T-bolt 63 is stopped on the plunger 68 thusy advancing the grinding wheel to grind off half of t-he total amount to be finally removed from the gear tooth. The operation of the machine continues, grinding all of the teeth of the gear once around. The hand wheel 55 is hand wheel 51 up another notch, thus obviating any necessity for readjusting thestops 62l and 262 due to continueduse and redressing of the wheel.

The invention thus provides means to position the planular face 47 of the grinding wheel to accurately locate itin or maintain it in or restore it to a preselected plane on the machine determined by a reference station thereon; and to accurately control and predetermine the position of the plane at known distances therefrom; and the invention also provides means for preventing the plane of ythe Wheel face from moving out of its predetermined positions upon thermal expansion .of the wheel shaft by locating the end thrust bearings ol. the .shaft relative to lthe reference station. n

In Fig. 9 isfshown the application of the invention to a grinding machine for grinding cylinders or shafts 200, or the like, sup ported on centers 201-201. The grinding wheel 202 supported in bearings 203-203 on a slide 204 is adapted to be adj ustably reciprocated toward and from the work on ways 205 by a hand screw 206, which is anchored to the slide 204 at 207 and threaded into a stationary nut 208 on a main slide 209 reciprocable on ways 210. The dressing element 211 is mounted in a holder 212 screwed into a support 213 reciprocable on ways 214.

In operation the dressing element support 213 is moved to the right and the dressing element 211 is screwed in or out to bring it into contact with the reference station 215. And

Awhen thus adjusted, the support 213, is moved to the left and is reciprocatedback and forth Vment by the handwheel'206. If preferred the wheel ymay be moved back and forth across the dressing element 211 by reciprocating the slide 209. When the wheel has been dressed the slide 209 is moved to the leftto bring the WheelV into engagement with the work and to grind the same.- Obviously the reference, station215 may be adjusted by the bolt and slot arrangement at 217 to bring the reference station 215 into kthe line or plane 216 of thel work; and whatever position it may have,the dressingelement may vbe adjusted to it and the wheel dressed by the element tobring the working surface of the wheel coincident with the line or plane 216 of the reference station.

EGT

The inventionr not limited to .the forms' shown'and described. As'will loe,V apparent:

the invention radmits "ofi embodiment in' va:-

rions modifications Withinthe scope of the claims. n

I claim: l. In an apparatus for giving true shape and position to the planularY face of the grinding wheel of `a gear grinding machine,

a main frame, means for moving the grindv ing Wheel axiallyfonv-the frame, a stop device for stoppingtlie saidY axial movement of the Wheel at a Working position' thereof, andy means `for dressing the lplanularface yof the Wheel into coincidencey with a predetermined plane on the frame when in said stoppedl Working position, said Ymeans including a dressing reference Vstation on the fra-me, a

dressing yelement mounted for movement into engagement with the reference stationto powsition the element, and mounted *for movement in said predetermined plane.-

2. In an apparatus forgiving true shape andposition to the planular face oftheV grinding wheel of a gear grinding'n'iachine,

afmain `frame,,means for moving the grindg ingvvheel axially on the'frame, astop device; for stopping the said axial movement of the- Wheelsat a working, position thereof, and means for dressing the planular face of the wheel into coneidencewith a predetermined plane on the frame -Whenin said stopped Working position, said meansV including 'a dressing reference station kon the frame, a dressing elementmounted for movementinto engagement. with ythe referencestationto fpo` sition, said.V means -incl.udin,f':rk a dressingrref-a erence station: on the frame,sa dressing elej ment mounted foi'movementinto engages ment With the reference station to position thefe'lernentand monnte'd for movementfin said predetermined plane, l and fait-Xifli'i'ryV means vvherebythewheel may befed. beyond said final positionfindependently of the stop? ping means, to' feed'the vVheelintoF the path ofthe dressing element." i

e" in. air apparatus for givingtrne shape andfposition tothe plarmflar face-'of` the grindin'gwheel of al gear grinding machine, a main frame, a' spindle; for the Wheel onV the* frame, means for" moving, the' Wheel spindle en-dwise f element when operated, a y Y means 'disconnectibly connected with the iirsty operable means and adjustable relative thereon the frame, said means including. an element v associated with the Wheel spindle adapted to be moved to move the spindley end- Wise, a first operable means associated With said spindlemoving element for moving the secondV operable to when disconnected, a stop on the frame and an stop on4 the second operable means adapted to engage the stop on the-fra1ne,

whereby the second operable means may bevr moved to mutually engage the stops to position ythe planular face of the Wheel in apredetermined Worln'ng plane on the `machine and whereby the first yand second operable* means may be Yadjusted relatively to each otherl to shift the said stopped position ofthe ivheelto permit its being dressed 0E in said .fplanef a'dressing reference station on the frame, a dressing element on the frame mountedfor movement into engagement vvithy the reference station to position the element 4 and *mounted for movement in said predetermined plane to dress the planular face of the Wheel; v f i 5, lnf'an apparatus for giving true shape and position to theplannlar face of the grind ing Wheel of agear grinding machine, a main frame,ia spindlefortlie Wheel on' the frame,

means for movingthe Wheel spindle endvvise on the frame, said means including a pair of meslied screw threaded elements the lirst of o which is connected with the tool spindle and the second ,of which is adapted when rotated to propel the first and thereby move the spin- Y dle endvvise, an operable' element, conneev tions between the operable element andthe Second screw threaded element forrotatingthe/latter; a handr operable element discon-v V; nectibly connected with the'operable" element and r adjustable inxpositi'on relative thereto when disconnected therefrom, a stop on the frame, a stop on thehand operable element adapted to engage the stop on; the frame,- Whereby the hand operable elementlmaybe moved to mutually enga-ge the stops to pos-i:

tion the pl'annlar face of the'wvheel, in a predetermined Working plane on the"machine, and rwhereby the tvvo .operable elements may be adjustedfrelative to each other toV shift the' said 'stopped position of the "Wheel face to permit its being' dressed ofi' yin lsaid', plane, a dressing `reference station Yon the fframe, a

dressing lelement .onthe frame mounted for t movement into engagement with the .refer-v ence station to position the element and mounted for movement in said predeter= mined plane to dress theplannflar'face ofthe 6.- In-an apparaftus` for'givingutrue shape and position l toy the working; surface fof; the

grinding wheel o-f-a grinding machine, a main Y frame, means for moving the grinding Wheel on the frame, a stopfdevice for stoppingithe movement of the wheel at a working position Y on the frame, and means for dressing the working surface of the wheel into coincidence with a predetermined workin zone on the machine when in said stoppe working position, said' means including a dressing reference station on the frame, a dressing element mounted for movement into engagement with the reference station to position the element, and mounted for movement in a predetermined path on the frame to dress the working surface of the wheel.

7. In an apparatus shape and positlon to the wor ing surface of the grinding wheel of a grinding machine, a main frame, means for moving the grinding wheel on the frame, a stop device for stopping the movement of the Wheel at a working position on the frame, and means for dressing the working surface of the wheel into coincidence with a. predetermined working zone on the machine when in said stopped working position, said means including a dressing reference station on the frame, a dressing element mounted for movement into engagement with the reference station to position the element, and mountedfor movement in a predetermined ath on the frame to dress the working sur ace of the wheel, and auxiliary means whereby the wheel may be moved beyond said stopped position into the path ofthe dressing element.

8. In a grinding apparatus comprising a main frame, a drinding wheel and a wheel spindle, means or moving the wheel spindle to feed the wheel relative to the work, means for stopping the feed at a final working position, and means for dressing the working surface of the wheel when in said final stopped position to bring it into coincidence 'with a predetermined working zone on the machine, said means including a dressing reference sta-tion on the frame, and a dressing element mountedk for movement into engagement with the reference station to position the element, and mounted for movement to dress said working surface.

9. In an apparatus for giving true shape and position to the planular face-of the grinding wheel of a gear grinding machine, a main frame, means for moving the grinding wheel on the frame in a direction transversely of its grinding face, a stop device for normally stopping the movement of the wheel with its planular face at a working position thereof, means for moving the wheel transversely of its face, a preselected amount independently of the stop device whereby it may be positioned in a second stopped position determined by said stop device and means for dressing the planular face of the wheel into coincidence with a predetermined plane on the frame when in said second stopped position.

10. In a gear grinding apparatus comprisfor giving truek ing a main frame and a generally axially movable planular faced Vgrinding wheel, means for moving the wheel generally axially to feed `it relative to the work, means -for stoppin the feed at a final working position, means or causing the wheel to be stopped after an increment of movement beyon the working position and means for dressing the planularface of the wheel into coincidence with a predetermined plane on the machine when in said stopped position. n

11. In an apparatus for givingtrue shape and position tothe working surface of the rinding wheel of a grinding machine, a main rame, means for moving the grindingwheel on the frame, a stop device for normally stopping'the movement of the wheel lat a working osition on the frame, means whereby the w eel may be Lmoved a preselected increment beyond the workingposition to a second stopped position determined by said stop device, and means for dressing the working surface of the wheel into coincidence with a predetermined working zone'on the machine when in said second stopped position. 12.y In an apparatus for giving true shape and position to the planular face of the grinding wheel of a gear grinding machine, a main frame, means for moving the wheel generally axially on the frame, an element associated with the wheel adapted to be moved to move the wheel, a .first operable means yassociated with the wheel moving element for moving the element when operated, a second operable means disconnectibly connected with the lirst operable means and'adjustable relative thereto when disconnected therefrom, a stop on the frame and a stop on the second operable means adapted to engage the stop on the frame, ywhereby the second Voperable means may be moved to mutually engage the stops to position the planular face of the wheelin a redetermined working plane on the machine and whereby the first and second operable means may be adjusted relatively to each other to shift the said position at which the wheel yis stopped to permit its being dressed o in said plane, a dressing reference statlon on the frame, a dressing element on the frame mounted for movement into engagement with the reference station to position the element and mounted for movement in said predetermined plane to dress ythe planular face of the wheel.

V13.k In an apparatusfor giving true shape and position to the planular face of the grinding wheel of a gear grinding machine, a. main frame, a spindle for the wheel on the frame, means'for moving the wheel spindle endwise on the frame, said means including an element associated with the wheel spindle adapted to be moved to move the spindle endwise, a first operable means associated with said spindle movin g element for moving the element when operated, a second operable means disoonneotibly Connected Withthe first operable means and adjustable relativethereto when disconnected, a stop on the frame and a stop on the second operable means adapted to engage the stop` on the frame, whereby the second operable means may be moved to mutually engage the stops to position the planular face of the Wheel in a predetermined Working plane on the machine f and whereby the first and second operable means may be adjusted 4relatively to each other to shift the saidstopped position of the Wheel to permit its being dressed olf in said plane, a dressing reference station on the frame, a dressing element on the frame mounted for movement into engagement with the reference stationto position the element and mounted for oscillatory movement around an axis parallel to the axis of the Wheel spindle and in said predetermined plane to dress the planular face of the Wheel.

In ytestimony whereof,l Il` have yhereunto signed my name.

CHARLES H. SCHURR. 

